Correlation of milling time on formation of TiCoSb phase by mechanical alloying

Nanocrystalline TiCoSb powder was synthesized by mechanical alloying from elemental Ti, Co and Sb powders. The samples milled at different times were characterized by X-ray diffractometer (XRD) and scanning electron microscopy (SEM). The synthesized powder shows a half-Heusler phase in MgAgAs structure after 6 h of milling. The crystallite sizes decrease with increasing milling time. The minimum crystallite size is about 31.7 nm after 40 h of milling. The magnetic properties of this sample give evidence of the existence of ferromagnetic clusters as a secondary phase.